1. Technical Field
The present invention relates to a handoff system and method for a dual mode terminal.
2. Related Art
Due to the burgeoning demand for wireless networking, various wireless technologies such as third generation (3G), wireless local area network (WLAN), wireless broadband Internet (Wibro), etc., have recently been introduced. To take full advantage of the available technologies, development of a dual mode terminal which supports two or more wireless technologies, such as WLAN, Ethernet, the WAN, etc., based on the 3G technology has begun.
Accordingly, handover to a network of another layer should be considered in order to support seamless and stable service.
A dual mode terminal receives a router advertisement (RA) message from a foreign network while performing a handover, and transmits only location information about care-of address (COA) depending on RA while transmitting a registration request message to a home agent (HA).
In other words, the dual mode terminal can move to the foreign network having a different bandwidth (e.g., Wibro<->WLAN, WLAN<->3G, . . . ) in the handover between heterogeneous networks.
Particularly, in the case where a dual mode phone receives a large volume of media content from a content-providing server, such as a video-on-demand (VOD) server, while moving from a wide-bandwidth network (e.g., WLAN 11 Mbps) to a narrow-bandwidth network (e.g., Wibro 1-3 Mbps), a high load may be applied to a foreign router when the HA directly transmits the content of the dual mode phone to the foreign router.
Thus, the foreign router cannot transmit relevant content to the dual mode phone normally, thereby causing service interruption or a mosaic phenomenon due to data loss.